The deformation behavior and evolution process of dynamic recrystallization for GH761 superalloy were studied with isothermal compression test in the temperature range of 950 ℃~1150 ℃ and the strain rate range of 0.1 s-1~30 s-1. The effect of thermodynamic parameters on flow stress was analyzed. A constitutive relationship was proposed based on the Arrhenius equation for the GH761 superalloy. The initiation and evolution of dynamic recrystallization were investigated with quantitive microstructure analysis. The volume fracture and grain size of dynamic recrystallization were established as functions of the Zener-Hollomon parameter. It is found that the calculation results of the proposed model are well agreed with the experimental data. Therefore, the proposed model can lay foundation of the quality control and process design for the forging process of GH761 superalloy